Methods of fabricating a semiconductor device including fine patterns

ABSTRACT

Methods of fabricating a semiconductor device are provided. The method includes forming active lines in a semiconductor substrate, forming contact lines generally crossing over the active lines, forming line-shaped etch mask patterns generally crossing over the active lines and the contact lines, etching the contact lines exposed by the line-shaped etch mask patterns to form contact separation grooves and to form contact patterns generally remaining at intersections between the line-shaped etch mask patterns and the active lines, etching the active lines exposed by the contact separation grooves to form active separation grooves that generally divide each of the active lines into a plurality of active patterns, forming gates that substantially intersect the active patterns, and forming bit lines electrically connected to the contact patterns.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C 119(a) to KoreanApplication No. 10-2012-0010531, filed on Feb. 1, 2012, in the KoreanIntellectual Property Office, which is incorporated herein by referencein its entirety set forth in full.

BACKGROUND

1. Technical Field

Embodiments of the present disclosure relate to methods of fabricating asemiconductor device. Additionally, an embodiment of this disclosurerelates to methods of fabricating a semiconductor device including finepatterns.

As semiconductor devices become more highly integrated, various methodsof realizing fine and small patterns have been continuously developed.For example, as semiconductor memory devices such as dynamic randomaccess memory (DRAM) devices become increasingly integrated, cellpatterns constituting memory cells of the DRAM devices have been shrunkto a minimum feature size of about 30 nanometers or less. However, itmay be difficult to form the fine patterns having a minimum feature sizeof about 30 nanometers or less using a lithography process that employsa single exposure technique.

2. Related Art

According to general isolation technologies, a plurality of parallelline-shaped mask patterns are formed on a substrate, and predeterminedportions of the line-shaped patterns are etched and removed using acutting photo mask including hole-shaped opening patterns to form aplurality of separate active mask patterns which are two dimensionallyarrayed on the substrate. For example, a plurality of parallelline-shaped patterns may be formed on a substrate using a spacerpatterning technology, and predetermined portions of each of theline-shaped patterns may be removed using a cutting photo mask havinghole-shaped opening patterns to form a plurality of hole patterns thatdivide each of the line-shaped patterns into a plurality of separatedfine patterns.

In the fabrication of fine patterns using cutting photo masks withhole-shaped opening patterns, the size of the hole-shaped openingpatterns has been continuously reduced with the increase in theintegration density of semiconductor devices. Thus, there may be somelimitations in successfully cutting the line-shaped patterns without anymisalignment between the line-shaped patterns and the cutting photomask. In the event that the cutting photo masks, having the hole-shapedopening patterns, are misaligned with the line-shaped patterns on thesubstrate, lengths of the fine patterns may be non-uniform degrading thereliability and/or the electrical characteristics of the semiconductordevices.

SUMMARY

Embodiments are directed to methods of fabricating a semiconductordevice having fine patterns.

According to an embodiment, a method of fabricating a semiconductordevice may include forming a first isolation layer in a semiconductorsubstrate to define active lines; forming contact lines generallycrossing over the active lines and a first interlayer insulation layersubstantially filling spaces between the contact lines; formingline-shaped etch mask patterns generally crossing over the active linesand the contact lines; etching the contact lines exposed by theline-shaped etch mask patterns to form contact separation grooves and toform contact patterns generally remaining at intersections between theline-shaped etch mask patterns and the active lines; etching the activelines exposed by the contact separation grooves to form activeseparation grooves that generally divide each of the active lines into aplurality of active patterns; forming a third isolation layersubstantially filling the active separation grooves; forming gates thatsubstantially intersect the active patterns; and forming bit linesgenerally crossing over the gates.

Additionally, according to an embodiment, a method of fabricating asemiconductor device may include forming a first isolation layer in asemiconductor substrate to define active lines; forming pseudo contactlines generally crossing over the active lines and a first interlayerinsulation layer substantially filling spaces between the pseudo contactlines; forming line-shaped etch mask patterns generally crossing overthe active lines and the pseudo contact lines; etching the pseudocontact lines exposed by the line-shaped etch mask patterns to formcontact separation grooves and to form pseudo contact patterns generallyremaining at intersections between the line-shaped etch mask patternsand the active lines; etching the active lines exposed by the contactseparation grooves to form active separation grooves that generallydivide each of the active lines into a plurality of active patterns;forming a third isolation layer substantially filling the activeseparation grooves; forming gates that substantially intersect theactive patterns; removing the pseudo contact patterns to form contactholes; forming contact patterns substantially filling the contact holes;and forming bit lines connected to the contact patterns.

According to another embodiment, a method of fabricating a semiconductordevice may include forming a first isolation layer in a semiconductorsubstrate to define cell active lines in a cell region of thesemiconductor substrate and to define a peripheral active region in aperipheral circuit region of the semiconductor substrate; formingcontact lines that generally cross over the cell active lines and afirst interlayer insulation layer that substantially fills spacesbetween the contact lines and substantially covers the peripheralcircuit region; forming line-shaped etch mask patterns generallycrossing over the cell active lines and generally crossing over thecontact lines in the cell region; etching the contact lines exposed bythe line-shaped etch mask patterns to form contact separation groovesand to form contact patterns remaining at intersections between theline-shaped etch mask patterns and the cell active lines; etching thecell active lines exposed by the contact separation grooves to formactive separation grooves that generally divide each of the cell activelines into a plurality of cell active patterns; forming a thirdisolation layer filling the active separation grooves; forming buriedgates that substantially intersect the cell active patterns; selectivelyremoving the first interlayer insulation layer in the peripheral circuitregion to substantially expose the peripheral active region; forming afirst peripheral gate layer substantially on the peripheral circuitregion including the exposed peripheral active region; forming a bitline layer electrically connected to the contact patterns on an entiresurface of the substrate including the first peripheral gate layer; andpatterning the bit line layer and the first peripheral gate layer toform bit lines connected to the contact patterns in the cell region andto form a peripheral gate including a first peripheral gate and a secondperipheral gate in the peripheral circuit region, wherein the firstperipheral gate is a portion of the first peripheral gate layer and thesecond peripheral gate is a portion of the bit line layer.

According to still another embodiment, a method of fabricating asemiconductor device may include forming a first isolation layer in asemiconductor substrate to define cell active lines in a cell region ofthe semiconductor substrate and to define a peripheral active region ina peripheral circuit region of the semiconductor substrate; formingpseudo contact lines that generally cross over the cell active lines anda first interlayer insulation layer that substantially fills spacesbetween the pseudo contact lines and substantially covers the peripheralcircuit region; forming line-shaped etch mask patterns generallycrossing over the cell active lines and generally crossing over thepseudo contact lines in the cell region; etching the pseudo contactlines exposed by the line-shaped etch mask patterns to form contactseparation grooves and to form pseudo contact patterns remaining atintersections substantially between the line-shaped etch mask patternsand the cell active lines; etching the cell active lines exposed by thecontact separation grooves to form active separation grooves thatgenerally divide each of the cell active lines into a plurality of cellactive patterns; forming a third isolation layer filling the activeseparation grooves; forming buried gates that substantially intersectthe cell active patterns; selectively removing the pseudo contactpatterns to form contact holes; forming contact patterns substantiallyfilling the contact holes; selectively removing the first interlayerinsulation layer in the peripheral circuit region to substantiallyexpose the peripheral active region; forming a first peripheral gatelayer on the peripheral circuit region including the exposed peripheralactive region; forming a bit line layer electrically connected to thecontact patterns on an entire surface of the substrate including thefirst peripheral gate layer; and patterning the bit line layer and thefirst peripheral gate layer to form bit lines connected to the contactpatterns in the cell region and to form a peripheral gate including afirst peripheral gate and a second peripheral gate in the peripheralcircuit region, wherein the first peripheral gate is a portion of thefirst peripheral gate layer and the second peripheral gate is a portionof the bit line layer.

Finally, according to an embodiment, a method of fabricating asemiconductor device may include forming active lines in a semiconductorsubstrate; forming contact lines substantially crossing over the activelines; forming line-shaped etch mask patterns substantially crossingover the active lines and the contact lines; etching the contact linesexposed by the line-shaped etch mask patterns to form contact separationgrooves and to form contact patterns remaining at intersectionssubstantially between the line-shaped etch mask patterns and the activelines; etching the active lines exposed by the contact separationgrooves to form active separation grooves that generally divide each ofthe active lines into a plurality of active patterns; forming gates thatsubstantially intersect the active patterns; and forming bit lineselectrically connected to the contact patterns.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the inventive concept will become more apparent in viewof the attached drawings and accompanying detailed description.

FIGS. 1 to 34 illustrate an example of a method of fabricating asemiconductor device including fine patterns according to an embodiment.

FIG. 35 illustrates an example of a method of fabricating asemiconductor device including fine patterns according to anotherembodiment.

FIGS. 36 to 58 illustrate an example of a method of fabricating asemiconductor device including fine patterns according to still anotherembodiment.

DESCRIPTION OF THE EMBODIMENTS

Various embodiments are described below with reference to theaccompanying drawings. Many different forms and embodiments are possiblewithout deviating from the spirit and teachings of this disclosure andso the disclosure should not be construed as limited to the embodimentsset forth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will convey the scope ofthe disclosure to those skilled in the art. The drawings are notnecessarily to scale and in some instances, proportions may have beenexaggerated in order to clearly illustrate features of the embodiments.The same reference numerals or the same reference designators denote thesame elements throughout the specification.

Embodiments are described herein with reference to plan views andcross-section views that are schematic illustrations of idealizedembodiments (and intermediate structures). As such, variations from theshapes of the illustrations as a result, for example, of manufacturingtechniques and/or tolerances, are to be expected. Thus, theseembodiments may not be construed as limited to the particular shapes ofregions illustrated herein but may be construed to include deviations inshapes that result, for example, from manufacturing.

In this specification, specific terms have been used. The terms are usedto describe the present invention, and are not used to qualify the senseor limit the scope of the present invention. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “has”, “having”, “comprises,”“comprising,” “includes,” and/or “including,” when used herein, specifythe presence of stated features, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, steps, operations, elements, components, and/or groupsthereof.

It will be understood that when an element is referred to as being“coupled,” “connected,” or “responsive” to, or “on,” another element, itcan be directly coupled, connected, or responsive to, or on, the otherelement, or intervening elements may also be present. In contrast, whenan element is referred to as being “directly coupled,” “directlyconnected,” or “directly responsive” to, or “directly on,” anotherelement, there are no intervening elements present. As used herein, theterm “and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. Thus, a first element could be termed a secondelement without departing from the teachings of the present embodiments.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which these embodiments belong. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

According to embodiments described herein, a cutting photo mask fordividing line-shaped patterns disposed on a substrate into a pluralityof fine patterns may also include a plurality of line-shaped openingpatterns that are aligned to cross the line-shaped patterns. Thus, theoverlay margin between the line-shaped patterns and the cutting photomask may be increased to reduce process failures.

FIGS. 1 to 34 illustrate an example of a method of fabricating asemiconductor device including fine patterns according to an embodiment.Although the present embodiment is described in conjunction with cellactive regions and bit line contacts of dynamic random access memory(DRAM) devices, the inventive concepts may also be equally applicable toother layers of DRAM devices or to other semiconductor devices besidesthe DRAM devices.

FIG. 1 is an example of a cell layout diagram illustrating a cellisolation structure in a cell region of a semiconductor device (e.g., aDRAM device) according to an embodiment.

Referring to FIG. 1, a cell isolation layout 10 of a DRAM deviceaccording to an embodiment may include a cell isolation region 15defining cell active regions 11 on which cell transistors of memorycells may be disposed. Each of the cell active regions 11 may include amajor axis and a minor axis. A unit cell of the DRAM device may bedesigned to have a cell layout area of 6F² in order to increase theintegration density of the DRAM device. The character “F” of the celllayout area 6F² denotes a minimum feature size (MFS). In the 6F² celllayout, the cell active regions 11 may be disposed such that the majoraxes of the cell active regions 11 are non-parallel with both an x-axisand a y-axis of an orthogonal coordinate system having the x-axis andthe y-axis. For example, the cell active regions 11 may be disposedsubstantially in parallel with a generally diagonal line intersectingthe y-axis at an angle of about 18 degrees.

As the DRAM devices are scaled down to have a minimum feature size ofabout 30 nanometers or less, it may be difficult to directly transfercell active mask patterns corresponding to the cell active regions 11onto a substrate or a wafer without any pattern distortions using asingle exposure technique of a lithography process. Thus, in order tominimize the pattern distortions of the cell active regions 11, aplurality of generally parallel line-shaped patterns may be formed on asubstrate using a photo mask, and predetermined portions of theline-shaped patterns may be cut using another photo mask to form aplurality of substantially fine patterns acting as the cell active maskpatterns that correspond to the cell active regions 11.

FIGS. 2 and 3 illustrate process steps of forming isolation trenches 151and 153 in a semiconductor substrate 100.

FIG. 2 is a plan view illustrating a cell active line mask layout 20. Asillustrated in FIG. 2, a cell active line mask layout 20 may beextracted by connecting the cell active regions 11 in each of thediagonal lines intersecting the y-axis of FIG. 1 to each other. Thus,the cell active line mask layout 20 may include a plurality ofsubstantially parallel cell active line patterns 21. Space regions 25between the cell active line patterns 21 may correspond to the cellisolation region (15 of FIG. 1).

FIG. 3 is a cross sectional view illustrating an example of processsteps of forming isolation trenches 151 and 153 in a semiconductorsubstrate 100. The semiconductor substrate 100 may include a cell regionin which cell circuits including memory cells are integrated and aperipheral circuit region in which peripheral circuits controlling thecell circuits are integrated. If the semiconductor device is asemiconductor memory device such as a DRAM device as described above,memory cell elements such as cell capacitors and/or cell transistors maybe integrated in the cell region and peripheral circuit elements such asperipheral transistors constituting the peripheral circuits (e.g., senseamplifiers, row decoders, and/or column decoders, etc.) may beintegrated in the peripheral circuit region.

FIG. 3 is a merged cross-sectional view including a cell cross sectionalview taken along lines A-A′ and B-B′ of FIG. 2 and a peripheral circuitcross sectional view. Referring to FIG. 3, a trench etch mask 209 fordefining active regions may be formed on a semiconductor substrate 100.

The trench etch mask 209 may be formed to include a first trench etchmask 211 in the cell region and a second trench etch mask 213 in theperipheral circuit region. Specifically, a trench etch mask layer and aphotoresist layer may be sequentially formed on the semiconductorsubstrate 100, for example, a silicon substrate. The cell active linemask layout 20 of FIG. 2 may be transferred onto the photoresist layerin the cell region, and an additional mask layout may be transferredonto photoresist layer in the peripheral circuit region. The photoresistlayer may be patterned using a develop process, and the trench etch masklayer may be etched using the patterned photoresist layer as an etchmask. The patterned photoresist layer may be then removed. As a result,the trench etch mask 209 may be formed to include the first trench etchmask 211 in the cell region and the second trench etch mask 213 in theperipheral circuit region. The first trench etch mask 211 including fineline patterns (e.g., the cell active line patterns 21 of FIG. 2) may beformed using a fine pattern formation technology such as a spacerpatterning technology (SPT) that is appropriate for formation of a lineand space array.

The peripheral circuit region may include relatively large sizedpatterns as compared with the cell region. Thus, the spacer patterningtechnology (SPT) may not be applied to the peripheral circuit region.That is, the first trench etch mask 211 and the second trench etch mask213 may be independently formed using two separated exposure processesin order to apply the spacer patterning technology (SPT) to only thecell region. In some exemplary embodiments, the first trench etch mask211 having a line and space array may be formed using a doublepatterning technology (DPT), a double exposure technology (DET), alithography-lithography-etch (LLE) technology or alithography-etch-lithography-etch (LELE) technology instead of thespacer patterning technology (SPT).

Subsequently, the semiconductor substrate 100 may be etched using thetrench etch mask 209 as an etch mask, thereby first forming isolationtrenches 151 in the cell region and then a second isolation trench 153in the peripheral circuit region. The first isolation trenches 151 maybe formed to define cell active lines 111 corresponding to the cellactive line patterns 21 illustrated in FIG. 2, and the second trench 153may be formed to define peripheral active regions 113. Some portions ofEach of the cell active lines 111 defined by the line-shaped firsttrenches 151 may be cut in a subsequent process, thereby forming aplurality of fine patterns such as the cell active regions 11illustrated in FIG. 1. In contrast, each of the peripheral activeregions 113 may not be cut and/or divided into a plurality of finepatterns in a subsequent process.

FIGS. 4 and 5 illustrate an example of process steps of forming anisolation layer 230 in a semiconductor substrate 100. FIG. 4 is a planview illustrating an array layout of cell active lines 111 and firstisolation layers 231 in a cell region, and FIG. 5 is a mergedcross-sectional view including a cell cross sectional view taken alonglines A-A′ and B-B′ of FIG. 4 and a peripheral circuit cross sectionalview.

Referring to FIGS. 4 and 5, a trench liner 210 may be formed on bottomsurfaces and sidewalls of the first and second trenches 151 and 153. Thetrench liner 210 may be formed of an insulation layer. The trench liner210 may be formed by oxidizing the bottom surfaces and the sidewalls ofthe first and second trenches 151 and 153, respectively. For example,the trench liner 210 may be formed by thermally oxidizing the bottomsurfaces and the sidewalls of the first and second trenches 151 and 153,respectively. That is, the trench liner 210 may be formed of a thermaloxide layer. The trench liner 210 may be thinly formed. For example, thetrench liner 210 may be formed to a thickness of about several angstroms(A), about several ten angstroms (A) or about several hundred angstroms(A).

After the trench liner 210 is formed, an isolation layer 230 may beformed substantially on the substrate including the trench liner 210.The isolation layer 230, for example, an insulation layer may be formedto substantially fill the first and second trenches 151 and 153,respectively. In order to substantially fill both the first trenches 151and the second trench 153 wider than the first trenches 151 with theisolation layer 230, the isolation layer 230 in the cell region and theisolation layer 230 in the peripheral circuit region may be formedhaving different structures from each other.

In an embodiment, the first trenches 151 may be filled with a firstisolation layer 231 including a single-layered insulation material suchas a silicon nitride layer, and the second trench 153 may be filled withthe first isolation layer 231, the first isolation layer conforming toand formed substantially in the second trench 153 and a second isolationlayer 233 substantially filling the second trench 153 substantiallysurrounded by the first isolation layer 231. The second isolation layer233 may be formed of a generally flowable insulation layer having a gapfiling property, for example, a spin on dielectric (SOD) layer, etc. . .. . Thus, the second trench 153 may be filled with a multi-layeredinsulation material, whereas the first trenches 151 may be filled with asingle-layered insulation material. That is, the first isolation layer231 may be formed to fill the first trenches 151 and to conform to andsubstantially cover the bottom surface and the sidewalls of the secondtrench 153, and the second isolation layer 233 may be formedsubstantially on the first isolation layer 231 to substantially fill thesecond trench 153 generally surrounded by the first isolation layer 231.In the event that the second isolation layer 233 is formed of a spin ondielectric (SOD) layer, the SOD layer may be densified using anannealing process and the densified SOD layer (substantially,corresponding to a densified silicon oxide layer) may be then planarizedto form the first and second isolation layers 231 and 233, respectively,filling the second trench 153. The planarization process may beperformed until a top surface of the semiconductor substrate 100substantially outside the first and second trenches 151 and 153,respectively, is exposed. Alternatively, the planarization process maybe performed such that a portion of the first isolation layer 231remains generally on the top surface of the semiconductor substrate 100substantially outside the first and second trenches 151 and 153,respectively, to generally protect the semiconductor substrate 100.

The first isolation layer 231 may be formed of an insulation materialhaving an etch selectivity with respect to an interlayer insulationlayer that may be formed on the semiconductor substrate 100 in asubsequent process. In an embodiment, the first isolation layer 231 maybe formed of a silicon nitride layer to serve as an etch stop layerand/or to generally minimize the etch damage applied to thesemiconductor substrate 100 while the interlayer insulation layer ispatterned using an etching process.

Referring again to FIG. 4, each of the cell active lines 111 defined bythe first isolation layers 231 may be divided into the plurality of cellactive regions 11, illustrated in FIG. 1, in a subsequent process. Thatis, each of the cell active lines 111 may include cell active regionportions 117 and separation portions 118 or 119 generally between thecell active region portions 117.

The cell active regions 11 may be formed by forming a cutting maskpattern (not shown) having cutting holes substantially exposing theseparation portions 118 or 119 of the cell active lines 111 on thesemiconductor substrate including the isolation layer 230 and byselectively etching the substantially exposed separation portions 118 or119 using the cutting mask pattern as an etch mask to substantially keepthe cell active region portions 117 separated from each other.

When the cutting mask pattern having the cutting holes substantiallyexposing the separation portions 118 and 119 is formed generally on thesemiconductor substrate, there may be some difficulties in forming thecutting mask pattern. For example, as the semiconductor devices arescaled down to have a minimum feature size of about 30 nanometers orless, a pitch size of the separation portions 118 and 119 may bereduced. Thus, it may be difficult to directly transfer the cuttingholes exposing the separation portions 118 or 119 onto the semiconductorsubstrate without any pattern distortions using a single exposuretechnique of a lithography process. Accordingly, to overcome thedisadvantages of the single exposure technique, a double patterningtechnology (DPT) utilizing two photo masks may be used to form the cellactive regions 11, minimizing pattern distortions. That is, odd-numberedseparation portions 118 (e.g., first separation portions) may be exposedby first cutting holes that may be formed using a first cutting photomask, and even-numbered separation portions 119 (second separationportions) may be exposed by second cutting holes that may be formedusing a second cutting photo mask.

As described above, a fine pattern formation technology such as the DPTmay utilize two separated cutting photo masks. Thus, the DPT may requiretwo separated exposure steps and a careful alignment between the firstcutting photo mask and the second cutting photo mask, thereby increasingfabrication costs and process failure probabilities. As a result,uniformity of the cutting holes may be degraded to cause non-uniformityof the length of the cell active region portions 117, and an overlaymargin (e.g., an alignment margin) between the cell active regionportions 117 (e.g., cell active regions 11) and buried gates and/or bitlines formed in the subsequent processes may also be reduced.

The inventive concepts may provide methods of selectively removing theseparation portions 118 and 119 even without the use of cutting photomasks that include hole-shaped opening patterns that correspond to thecutting holes exposing the separation portions 118 and 119.

FIGS. 6 and 7 illustrate an example of process steps for formingline-shaped contact grooves 330 in a first interlayer insulation layer310. FIG. 6 is a plan view illustrating an array layout of line-shapedcontact grooves 330 in a cell region, and FIG. 7 is a mergedcross-sectional view including a cell cross sectional view taken alonglines A-A′ and B-B′ of FIG. 6 and a peripheral circuit cross sectionalview.

Referring to FIGS. 6 and 7, after planarization of the isolation layer230 substantially filling the first and second trenches 151 and 153,respectively, a first interlayer insulation layer 310 may be formedgenerally on the semiconductor substrate 100. The first interlayerinsulation layer 310 may be formed to include an insulation material(e.g., a silicon oxide layer) having an etch selectivity with respect tothe first isolation layer 231. This may be for preventing the firstisolation layer 231 in the cell region from being over etched or damagedwhile the first interlayer insulation layer 310 may be etched andpatterned in a subsequent process.

After formation of the first interlayer insulation layer 310, the firstinterlayer insulation layer 310 may be etched to form a plurality ofline-shaped contact grooves 330 in the cell region. The line-shapedcontact grooves 330 may be formed to substantially cross over the cellactive lines 111. A layout of the line-shaped contact grooves 330 may beextracted from a layout of the cell active lines 111 illustrated in FIG.4. That is, the separation portions 118 and 119 of the cell active lines111 may be connected to create generally diagonal lines substantiallyintersecting the cell active lines 111, and the diagonal linesconnecting the separation portions 118 and 119 may be changed intogenerally line-shaped rectangular patterns corresponding to theline-shaped contact grooves 330 illustrated in FIG. 6. The line-shapedcontact grooves 330 may include odd-numbered grooves and even-numberedgrooves. The odd-numbered grooves of the line-shaped contact grooves 330may be formed to generally expose the first separation portions 118, andthe even-numbered grooves of the line-shaped contact grooves 330 may beformed to generally expose the second separation portions 119.

The line-shaped contact grooves 330 may be formed to extend in adirection intersecting the cell active lines 111, as illustrated in FIG.6. Thus, the line-shaped contact grooves 330 may be formed to cross overcentral portions of the cell active region portions 117. For example,the line-shaped contact grooves 330 may be formed to generally exposethe central portions of the cell active region portions 117. The exposedcentral portions of the cell active region portions 117 may correspondto bit line contact regions 115.

In order to form the line-shaped contact grooves 330 in the cell region,a cutting photo mask having the layout of FIG. 6 may be manufactured andthe first interlayer insulation layer 310 may be patterned using anexposure process utilizing the cutting photo mask and an etchingprocess.

FIGS. 8 and 9 illustrate process steps of forming contact lines 430 inthe line-shaped contact grooves 330. FIG. 8 is a plan view illustratingan array layout of contact lines 430 in the cell region, and FIG. 9 is amerged cross-sectional view including a cell cross sectional view takenalong lines A-A′ and B-B′ of FIG. 8 and a peripheral circuit crosssectional view.

Referring to FIGS. 8 and 9, a spacer insulation layer may be conformedto and on the semiconductor substrate including the line-shaped contactgrooves 330. The spacer insulation layer may be anisotropically etchedto form first spacers 431 on sidewalls of the line-shaped contactgrooves 330 and to generally expose the bit line contact regions 115 andthe separation portions 118 and 119. Subsequently, a conductive layermay be deposited substantially on the substrate including the firstspacers 431, and the conductive layer may be planarized to form contactlines 430 in respective line-shaped contact grooves 330. The conductivelayer may be planarized using a chemical mechanical polishing (CMP)process. The conductive layer may be formed to include a dopedpolysilicon layer and/or a metal layer (e.g., a tungsten (W) layer or atitanium nitride (TiN) layer, etc.).

FIGS. 10 and 11 illustrate process steps of forming contact separationmask patterns 450. FIG. 10 is a plan view illustrating an array layoutof contact separation mask patterns 450 in the cell region, and FIG. 11is a merged cross-sectional view including a cell cross sectional viewtaken along lines A-A′ and B-B′ of FIG. 10 and a peripheral circuitcross sectional view.

Referring to FIGS. 10 and 11, contact separation mask patterns 450(e.g., line-shaped etch mask patterns) may be formed generally on thesubstrate including the contact lines 430 (see FIG. 8). The contactseparation mask patterns 450 may be formed to extend in a directionintersecting the contact lines 430. For example, the contact separationmask patterns 450 may be formed to be perpendicular or generallyperpendicular to the contact lines 430. A layout of the contactseparation mask patterns 450 may be extracted and/or generated from alayout of the contact lines 430 illustrated in FIG. 8. That is, the bitline contact regions 115 (see FIG. 7) may be connected to creatediagonal or generally diagonal lines intersecting the contact lines 430at a right angle or generally a right angle, and the substantiallydiagonal lines connecting the bit line contact regions 115 may bechanged into line-shaped rectangular patterns or substantial rectangularpatterns corresponding to the contact separation mask patterns 450illustrated in FIG. 10.

To form the contact separation mask patterns 450, an insulation layermay be formed to generally cover the first interlayer insulation layer310 and the contact lines 430 (see FIG. 9), and the insulation layer maybe patterned using a lithography process utilizing a photo mask havingthe layout of the contact separation mask patterns 450 and an etchingprocess. The contact separation mask patterns 450 may be formed of aninsulation material having an etch selectivity with respect to thesemiconductor substrate 100 (e.g., a silicon substrate), the contactlines 430 (e.g., a doped polysilicon layer) and the first interlayerinsulation layer 310 (e.g., a silicon oxide layer). For example, thecontact separation mask patterns 450 may be formed to include a siliconnitride layer, etc.

The contact lines 430 (see FIG. 9) may be etched using the contactseparation mask patterns 450 as an etch mask. The etching processapplied to the contact lines 430 may selectively remove portions of thecontact lines 430 exposed by the contact separation mask patterns 450because the contact separation mask patterns 450 has an etch selectivitywith respect to the contact lines 430. The etching process applied tothe contact lines 430 may be performed using a dry etching process.While the contact lines 430 are etched using the contact separation maskpatterns 450 as an etch mask, the first interlayer insulation layer 310(e.g., a silicon oxide layer) may not be over-etched because the firstinterlayer insulation layer 310 (e.g., a silicon oxide layer) has anetch selectivity with respect to the contact lines 430. As a result ofthe etching process applied to the exposed portions of the contact lines430, contact patterns 435 may be formed on respective bit line contactregions 115 (see FIG. 8) and contact separation grooves 433 may beformed substantially between the contact patterns 435 disposed in eachof the line-shaped contact grooves (see 330 of FIGS. 8 and 9). Thecontact patterns 435 may be generally located on respective bit linecontact regions 115, thereby acting as bit line contacts thatelectrically connect the bit line contact regions 115 to bit linesformed in a subsequent process.

The contact patterns 435 may be formed by etching the contact lines 430using the line-shaped contact separation mask patterns 450 generallyintersecting the contact lines 430 as an etch mask. Thus, even though apitch size of the contact patterns 435 may be reduced, the contactpatterns 435 may be more readily formed minimizing pattern distortionsor without any pattern distortions.

In the event that the contact patterns 435 are formed with a photo maskhaving island-shaped patterns generally corresponding to the contactpatterns 435, generally island-shaped mask patterns instead of theline-shaped contact separation mask patterns 450 may be formed on thesubstrate. In this case, if spaces between the adjacent contact patterns435 are reduced, the contact patterns 435 may be non-uniformly formedwith pattern distortions. Thus, it may be difficult to directly transferthe island-shaped patterns of the photo mask onto the substrate withoutany pattern distortions using a single exposure technique of alithography process.

To overcome the disadvantages of the single exposure technique, a doublepatterning technology (DPT) utilizing two separated photo masks may beused to form the contact patterns 435 with minimization of patterndistortions. Thus, the DPT may require two separated exposure steps anda careful alignment between two lithography processes performed usingtwo separated photo masks, thereby increasing the fabrication cost andthe process failure probability. However, according to the inventiveconcepts, the contact patterns 435 may be uniformly formed generallywithout pattern distortions using a single photo mask having a layoutcorresponding to the line-shaped contact separation mask patterns 450that substantially intersect the contact lines 430, as described above.Consequently, the disadvantages of the double patterning technology(DPT) can be overcome.

FIGS. 12 and 13 illustrate process steps of forming active separationgrooves 143. FIG. 12 is a plan view illustrating an array layout ofactive separation grooves 143 in the cell region, and FIG. 13 is amerged cross-sectional view including a cell cross sectional view takenalong lines A-A′ and B-B′ of FIG. 12 and a peripheral circuit crosssectional view.

Referring to FIGS. 12 and 13, the contact separation grooves 433 maygenerally expose portions of the semiconductor substrate 100corresponding to the separation portions 118 or 119 of the cell activelines 111. The contact separation grooves 433 may correspond to regionswhich are defined and exposed by the line-shaped contact separation maskpatterns 450 and the first interlayer insulation layer 310 when viewedfrom a plan view. The exposed portions of the semiconductor substrate100 (e.g., the exposed separation portions 118 or 119) may beselectively etched to form active separation grooves 143 thatsubstantially divide each of the cell active lines 111 into a pluralityof cell active patterns 141 corresponding to the cell active regionportions 117.

The active separation grooves 143 may be defined by the first interlayerinsulation layer 310, the first isolation layer 231 exposed by thecontact separation grooves 433, and line-shaped contact separation maskpatterns 450 when viewed from a plan view. Thus, the active separationgrooves 143 may be formed by selectively etching the exposed siliconsubstrate 100 using an etching recipe that exhibits an etch selectivitywith respect to the first interlayer insulation layer 310, the firstisolation layer 231 and the line-shaped contact separation mask patterns450. For example, in the event that the first interlayer insulationlayer 310 is generally formed of a silicon oxide layer and the firstisolation layer 231 and the line-shaped contact separation mask patterns450 are generally formed of a silicon nitride layer, the exposed siliconsubstrate 100 can be selectively etched using an etching recipe thatexhibits an etch selectivity with respect to a silicon oxide layer and asilicon nitride layer.

The active separation grooves 143 may be formed to be generallyself-aligned with the first interlayer insulation layer 310, the firstisolation layer 231 and the line-shaped contact separation mask patterns450. Thus, an additional cutting photo mask including hole-shapedopening patterns corresponding to the active separation grooves 143 maynot be required to form the active separation grooves 143. Accordingly,the aforementioned exemplary embodiments may remove some disadvantages(e.g., pattern distortions or the like) occurred when the additionalcutting photo mask including hole-shaped opening patterns is used toform the active separation grooves 143.

FIG. 14 is a plan view illustrating an array layout of third isolationlayers 235 substantially filling the active separation grooves 143 (seeFIG. 13) in the cell region, and FIG. 15 is a merged cross-sectionalview including a cell cross sectional view taken along lines A-A′ andB-B′ of FIG. 14 and a peripheral circuit cross sectional view.

Referring to FIGS. 14 and 15, third isolation layers 235 may be formedto substantially fill the active separation grooves 143. Specifically, aseparation groove liner 215, for example, an insulation layer may beconformed to cover the bottom surfaces and sidewalls of the activeseparation grooves 143. The separation groove liner 215 may be formed ofthe same material as the trench liner 210. For example, the separationgroove liner 215 may be formed of a thermal oxide layer. Subsequently,an insulation layer may be formed on the substrate including theseparation groove liner 215. The insulation layer may be then planarizeduntil top surfaces of the line-shaped contact separation mask patterns450 are substantially exposed, thereby forming third isolation layers235 substantially within the active separation grooves 143 (see FIG. 13)and the contact separation grooves 433 (see FIG. 13). In an exemplaryembodiment, the third isolation layers 235 may be formed of the samematerial as the first isolation layer 231.

FIG. 16 is a plan view illustrating an array layout of recessed thirdisolation layers 235 in the cell region, and FIG. 17 is a mergedcross-sectional view including a cell cross sectional view taken alonglines A-A′ and B-B′ of FIG. 16 and a peripheral circuit cross sectionalview.

Referring to FIGS. 16 and 17, the third isolation layers 235 may berecessed to reduce the burdens associated with the etching processesperformed in subsequent processes. Additionally, the third isolationlayers 235 and the line-shaped contact separation mask patterns 450 maybe planarized until top surfaces of the contact patterns 435 and thefirst interlayer insulation layer 310 are substantially exposed, and theplanarized third isolation layers 235 may be recessed such that topsurfaces of the recessed third isolation layers 235 are substantiallycoplanar with top surfaces of the cell active patterns 141. As a result,recessed grooves 334 may be formed on the recessed third isolationlayers 235. An insulation layer, for example, a silicon nitride layermay be conformed to and on the substrate including the recessed grooves334, and the insulation layer may be anisotropically etched tosubstantially expose the top surface of the first interlayer insulationlayer 310. As a result, second spacers 432 may be formed on thesidewalls of the contact patterns 435 and the sidewalls of the firstinterlayer insulation layer 310, which are exposed by the recessedgrooves 334.

Subsequently, second interlayer insulation layers 335 may be formed tosubstantially fill the recessed grooves 334 that are generallysurrounded by the second spacers 432. The second interlayer insulationlayers 335 may be formed of substantially the same material as the firstinterlayer insulation layer 310. The second interlayer insulation layers335 may be formed by depositing an insulation layer generally on thesubstrate including the second spacers 432 and by planarizing theinsulation layer to substantially expose the top surfaces of the contactpatterns 435 and the top surface of the first interlayer insulationlayer 310.

FIG. 18 is a plan view illustrating an array layout of buried gategrooves 501 in the cell region, and the FIG. 19 is a mergedcross-sectional view including a cell cross sectional view taken alonglines A-A′ and B-B′ of FIG. 18 and a peripheral circuit cross sectionalview.

Referring to FIGS. 18 and 19, a plurality of buried gate grooves 501 maybe formed to generally cross the cell active patterns 141. The buriedgate grooves 501 may be formed by etching the first interlayerinsulation layer 310, the second interlayer insulation layers 335, therecessed third isolation layers 235 and the cell active patterns 141.The buried gate grooves 501 may be formed to be parallel with an x-axisgenerally perpendicular to the y-axis in a plan view. In addition, eachof the cell active patterns 141 may be divided into three regions by apair of buried gate grooves 501 intersecting the same, and the contactpatterns 435 may be disposed substantially between the buried gategrooves 501. Thus, the buried gate grooves 501 may not overlap withcontact patterns 435 when viewed from a plan view.

FIG. 20 is a plan view illustrating an array layout of buried gatelayers 510 in the cell region, and FIG. 21 is a merged cross-sectionalview including a cell cross sectional view taken along lines A-A′ andB-B′ of FIG. 20 and a peripheral circuit cross sectional view.

Referring to FIGS. 20 and 21, a gate dielectric layer may be formedgenerally on inner surfaces of the buried gate grooves 501, and a gateconductive layer may be formed generally on the substrate including thegate dielectric layer. The gate conductive layer may be formed toinclude a metal layer, for example, a titanium nitride (TiN) layer or atungsten (W) layer etc. The gate conductive layer may be formed tosubstantially fill the buried gate grooves 501. The gate conductivelayer may then be planarized until the top surfaces of the contactpatterns 435 are substantially exposed, thereby forming buried gates 510in respective buried gate grooves 501.

FIG. 22 is a plan view illustrating an array layout of recessed buriedgates 511 in the cell region, and FIG. 23 is a merged cross-sectionalview including a cell cross sectional view taken along lines A-A′ andB-B′ of FIG. 22 and a peripheral circuit cross sectional view.

Referring to FIGS. 22 and 23, the buried gates 510 (see FIG. 21) may beselectively etched to recess the buried gates 510 and to form sealinggrooves 513 substantially on the recessed buried gates 511. Thus, topsurfaces of the recessed buried gates 511 may be located at a lowerlevel than top surfaces of the cell active patterns 141.

FIG. 24 is a plan view illustrating an array layout of sealing layers530 on the recessed buried gates 511 (see FIG. 23) in the cell region,and FIG. 25 is a merged cross-sectional view including a cell crosssectional view taken along lines A-A′ and B-B′ of FIG. 24 and aperipheral circuit cross sectional view.

Referring to FIGS. 24 and 25, a sealing layer 530 may be deposited onthe substrate including the sealing grooves 513 (see FIG. 23). Thesealing layer 530 may be formed to substantially fill the sealinggrooves 513. The sealing layer 530 may be formed of an insulationmaterial having an etch selectivity with respect to the first and secondinterlayer insulation layers 310 and 335 to substantially protect therecessed buried gates 511 when a subsequent etching process isperformed. For example, when the first and second interlayer insulationlayers 310 and 335 are formed of a silicon oxide layer, the sealinglayer 530 may be formed to include a silicon nitride layer.

FIG. 26 is a merged cross-sectional view illustrating process steps offorming a first peripheral gate layer 551.

Referring to FIG. 26, the sealing layer 530 and the first interlayerinsulation layer 310 in the peripheral circuit region may be selectivelyremoved to substantially expose top surfaces of the peripheral activeregions 113. Specifically, a peripheral open mask pattern (not shown)may be formed generally on the sealing layer 530. The peripheral openmask pattern may be formed to substantially cover the sealing layer 530in the cell region and to substantially expose the sealing layer 530 inthe peripheral circuit region. The sealing layer 530 and the firstinterlayer insulation layer 310 in the peripheral circuit region may beselectively etched using the peripheral open mask pattern as an etchmask, thereby substantially exposing the top surfaces of the peripheralactive regions 113. After the peripheral open mask pattern is removed, aperipheral gate dielectric layer 552 may be formed generally on theexposed top surfaces of the peripheral active regions 113. Theperipheral gate dielectric layer 552 may be formed of a dielectric layersuch as a silicon oxide layer ect.

Subsequently, a conductive layer may be formed substantially on thesubstrate including the peripheral gate dielectric layer 552, and theconductive layer may be planarized to substantially expose a top surfaceof the sealing layer 530 in the cell region. As a result, a firstperipheral gate layer 551 may be formed substantially on the peripheralgate dielectric layer 552.

FIG. 27 is a merged cross-sectional view illustrating process steps offorming a bit line layer 570.

Referring to FIG. 27, the sealing layer 530 remaining in the cell regionmay be planarized to expose top surfaces of the contact patterns 435,the first interlayer insulation layer 310 and the second interlayerinsulation layers 335 (see FIG. 26). That is, the sealing layer 530 maybe etched back to leave sealing patterns 530 on respective recessedburied gates 511. A bit line layer 570 may be formed substantially onthe substrate including the sealing patterns 530. The bit line layer 570may be formed to include a conductive layer having a higher conductivitythan a doped polysilicon layer. For example, the bit line layer 570 maybe formed to include a metal layer such as a tungsten (W) layer, etc. Inan exemplary embodiment, a first barrier metal layer 575, for example, atitanium nitride (TiN) layer may be formed substantially on thesubstrate including the sealing patterns 530 before the bit line layer570 is formed.

The bit line layer 570 and the first barrier metal layer 575 may beformed to extend generally onto the peripheral circuit region. That is,the bit line layer 570 and the first barrier metal layer 575 may beformed to substantially cover the first peripheral gate layer 551 in theperipheral circuit region. The bit line layer 570 in the cell region(e.g., a first bit line layer 571) may be patterned in a subsequentprocess to form bit lines that control operation of memory cells of theDRAM device, and the bit line layer 570 in the peripheral circuit region(e.g., a second bit line layer 573) may be patterned in a subsequentprocess to form a second peripheral gate layer having a higherconductivity than the first peripheral gate layer 551. A bit linecapping layer 590 may be then formed substantially on the bit line layer570. The bit line capping layer 590 may be used as a hard mask layerprotecting the bit line layer 570. The bit line capping layer 590 may beformed to include a silicon nitride layer.

FIG. 28 is a plan view illustrating an array layout of bit line stacks577 in the cell region, and FIG. 29 is a merged cross-sectional viewincluding a cell cross sectional view taken along lines A-A′ and B-B′ ofFIG. 28 and a peripheral circuit cross sectional view.

Referring to FIGS. 28 and 29, an array layout corresponding to bit linestacks 577 may be generated to extend generally along the y-axisdirection intersecting the recessed buried gates 511 and tosubstantially overlap with the contact patterns 435, as illustrated inFIG. 28. The array layout corresponding to the bit line stacks 577 maybe transferred on the substrate using a lithography process, therebyforming a bit line mask pattern (not shown) on the bit line cappinglayer 590. The bit line mask pattern may be formed to include aplurality of line patterns (corresponding to the bit line stacks 577) inthe cell region and to substantially cover an entire portion of theperipheral circuit region. The bit line capping layer 590, the bit linelayer 570 and the first barrier metal layer 575 may be etched using thebit line mask pattern as an etch mask, thereby forming the bit linestacks 577. Each of the bit line stacks 577 may be formed to include afirst barrier metal pattern 575, a bit line 572, and a bit line cappingpattern 591 which may be sequentially stacked. The bit lines 572 may beformed to substantially overlap with the contact patterns 435, asillustrated in FIG. 28. Thus, the bit lines 572 may be electricallyconnected to the contact patterns 435. That is, the contact patterns 435may act as bit line contacts.

After the bit line stacks 577 are formed, the bit line mask pattern maybe removed. A peripheral gate mask pattern (not shown) may be thenformed substantially on the substrate where the bit line mask pattern isremoved. The peripheral gate mask pattern may be formed to substantiallycover the cell region and to include a peripheral gate pattern in theperipheral circuit region. The bit line capping layer 590, the bit linelayer 570, the first barrier metal layer 575, and the first peripheralgate layer 551 may be etched using the peripheral gate mask pattern asan etch mask, thereby forming at least one peripheral gate stack 578 inthe peripheral circuit region. Accordingly, the peripheral gate stack578 may be formed to include a first peripheral gate 554, a firstbarrier metal pattern 575, a second peripheral gate 574, and aperipheral gate capping pattern 593 which may be sequentially stacked.

As described above, the bit line stacks 577 and the peripheral gatestack 578 may be independently formed using two separated patterningprocesses. However, the inventive concept may not be limited thereto.For example, the bit line stacks 577 and the peripheral gate stack 578may be simultaneously formed or formed at generally the same time usinga single patterning process that may include a single exposure processand a single etching process if a process margin of the singlepatterning process is within an allowable range.

FIG. 30 is a merged cross-sectional view illustrating process steps offorming bit line spacers 587.

Referring to FIG. 30, a bit line spacer layer may be conformed to and onthe substrate including the bit line stacks 577 and the peripheral gatestack 578. The bit line spacer layer may be then anisotropically etchedto form bit line spacers 587 substantially covering the sidewalls of thebit line stacks 577, and peripheral gate spacers 588 substantiallycovering the sidewalls of the peripheral gate stack 578. The bit linespacers 587 and the peripheral gate spacers 588 may be formed of aninsulation material. For example, the bit line spacers 587 and theperipheral gate spacers 588 may be formed of a silicon nitride layerhaving an etch selectivity with respect to a silicon oxide layer.

FIG. 31 is a merged cross-sectional view illustrating process steps offorming a third interlayer insulation layer 350.

Referring to FIG. 31, a third interlayer insulation layer 350 may beformed to substantially fill spaces generally between the bit linestacks 577 as well as substantially between the peripheral gate stacks578. Specifically, an insulation layer, for example, a silicon oxidelayer may be formed substantially on the substrate including the bitline spacers 587 and the peripheral gate spacers 588. Subsequently, theinsulation layer may be planarized until top surfaces of the bit linestacks 577 and the peripheral gate stacks 578 are substantially exposed,thereby forming the third interlayer insulation layer 350.

FIG. 32 is a plan view illustrating a layout of a storage node contactmask pattern for forming storage node contact holes 601 in the cellregion, and FIG. 33 is a merged cross-sectional view including a cellcross sectional view taken along lines A-A′ and B-B′ of FIG. 32 and aperipheral circuit cross sectional view.

Referring to FIGS. 32 and 33, the third interlayer insulation layer 350and the first interlayer insulation layer 310 may be patterned to fromstorage node contact holes 601 that substantially expose both ends ofeach of the cell active patterns 141. The storage node contact holes 601may be formed by etching the third interlayer insulation layer 350 andthe first interlayer insulation layer 310 using a storage node contactmask pattern (not shown) as an etch mask. The storage node contact holes601 may be formed to generally be self-aligned with the bit line stacks577.

The storage node contact mask pattern may be formed on the substrateincluding the third interlayer insulation layer 350. The storage nodecontact mask pattern may be formed using a photo mask (not shown) thatincludes a layout pattern corresponding to line patterns 603 definingline-shaped grooves 602 that generally intersect the bit line stacks577. That is, the storage node contact mask pattern may be formed toinclude the line patterns 603 defining the line-shaped grooves 602 thatare generally parallel with the x-axis. The third interlayer insulationlayer 350 and the first interlayer insulation layer 310 may be etchedusing the storage node contact mask pattern as an etch mask, therebyforming the storage node contact holes 601. While the storage nodecontact holes 601 are formed, the bit line stacks 577 and the bit linespacers 587 exposed by the line-shaped grooves 602 may not besubstantially etched because the bit line capping patterns 591 and thebit line spacers 587 are formed of an insulation material (e.g., asilicon nitride layer) having an etch selectivity with respect to theinterlayer insulation layers 350 and 310 (e.g., silicon oxide layers).Thus, the storage node contact holes 601 may be formed to substantiallybe self-aligned with the bit line stacks 577 and the bit line spacers587.

FIG. 34 is a merged cross-sectional view illustrating process steps offorming storage node contacts 610 and storage nodes 630 in the cellregion.

Referring to FIG. 34, a conductive layer may be formed to substantiallyfill the storage node contact holes 601, and the conductive layer may beplanarized to substantially expose top surfaces of the third interlayerinsulation layer 350. As a result, storage node contacts 610 may beformed in respective storage node contact holes 601. The storage nodecontacts 610 may be formed to include a doped polysilicon layer.Subsequently, storage nodes 630 may be formed on respective storage nodecontacts 610. Each of the storage nodes 630 may be formed to generallyhave a pillar shape or a cylindrical shape. In some exemplaryembodiments, the storage nodes 630 may be formed of a metal layer suchas a titanium nitride (TiN) layer, etc. A dielectric layer (not shown)and a plate node (not shown) may be sequentially stacked substantiallyon the storage nodes 630 to form cell capacitors.

FIG. 35 illustrates an example of a method of fabricating asemiconductor device including fine patterns according to anotherembodiment. The present embodiment is similar to the previous embodimentdescribed with reference to FIGS. 1 to 34. Thus, to avoid duplicateexplanation, differences between the present embodiment and the previousembodiment illustrated in FIGS. 1 to 34 will mainly be described indetail hereinafter.

Referring to FIG. 35, the contact patterns 435 illustrated in FIG. 34may be formed of a doped polysilicon layer, contact patterns 473 of thepresent exemplary embodiment may be formed to include a metal layer suchas a tungsten (W) layer, etc. In the event that the contact patterns 473are formed of a metal layer, a second barrier metal layer 471 such as atitanium nitride (TiN) layer may be introduced substantially between thecell active patterns 141 (e.g., portions of the silicon substrate 100)and the contact patterns 473 (e.g., metal contact patterns). The metalcontact patterns 473 may have a relatively higher conductivity than thepolysilicon contact patterns 435. Thus, the metal contact patterns 473of the present exemplary embodiment may reduce the contact resistancebetween the bit lines 572 and the cell active patterns 141, therebyimproving the operation speed of the semiconductor device (e.g., a DRAMdevice).

FIGS. 36 to 58 illustrate a method of fabricating a semiconductor deviceincluding fine patterns according to still another embodiment.

According to the previous embodiments illustrated in FIGS. 1 to 35, thebit line contact patterns 435 or 473 may be formed before the recessedburied gates 511 are formed. In contrast, according to the presentembodiment, recessed buried gates may be formed before bit line contactpatterns are formed. This may lead to the improvement of the profile ofthe buried gate grooves (corresponding to the elements indicated bynumerals “501” of FIG. 18) and to the improvement of the uniformity ofthe buried gates (corresponding to the elements indicated by numerals“510” of FIGS. 20 and 21). In FIGS. 1 to 58, the same reference numeralsor the same reference designators denote the same elements orsubstantially equal elements from one figure to the next.

FIG. 36 is a merged cross-sectional view illustrating process steps offorming a third interlayer insulation layer 3100 substantially coveringfirst and second isolation layers 2310 and 2330.

Referring to FIG. 36, first trenches 1510 and second trench 1530 may beformed in a semiconductor substrate 1000 using the same manners asdescribed with reference to FIGS. 1 to 5. The first trenches 1510 andsecond trench 1530 may be formed in a cell region and a peripheralcircuit region, respectively. The first trenches 1510 may define cellactive lines 1110 in the cell region and the second trench 1530 maydefine peripheral active regions 1130 in the peripheral circuit region.Subsequently, a first isolation layer 2310 may be formed tosubstantially fill the first trenches 1510 and to generally conform toand cover the bottom surface and sidewalls of the second trench 1530,and a second isolation layer 2330 may be formed substantially on thefirst isolation layer 2310 to substantially fill the second trench 1530substantially surrounded by the first isolation layer 2310.

A third interlayer insulation layer 3100 may be formed substantially onthe substrate including the first isolation layer 2310 and the secondisolation layer 2330. That is, the substrate including the firstisolation layer 2310 and the second isolation layer 2330 may besubstantially covered with the third interlayer insulation layer 3100instead of the first interlayer insulation layer 310 described withreference to FIG. 7. The third interlayer insulation layer 3100 may beformed to include a silicon nitride layer. A pad oxide layer 3110 may beformed substantially between the third interlayer insulation layer 3100and the semiconductor substrate 1000. The pad oxide layer 3110 may beformed to improve an interface characteristic (e.g., an adhesiveproperty) between the third interlayer insulation layer 3100 and thesemiconductor substrate 1000. The material of the third interlayerinsulation layer 3100 may not be limited to a silicon nitride layer. Forexample, the third interlayer insulation layer 3100 may be formed of anyother insulation layer having an etch selectivity with respect to asilicon oxide layer.

The third interlayer insulation layer 3100 may function as a moldinglayer in which bit line contacts may be formed in a subsequent process.Further, the third interlayer insulation layer 3100 may be used as asacrificial insulation layer. Accordingly, a thickness of the thirdinterlayer insulation layer 3100 may be determined in consideration witha height of the bit line contacts. For example, the third interlayerinsulation layer 3100 may be formed to have a thickness which issubstantially equal to the height of the bit line contacts.

FIG. 37 is a plan view illustrating an array layout of line-shapedcontact grooves 3300 in a cell region, and FIG. 38 is a mergedcross-sectional view including a cell cross sectional view taken alonglines A-A′ and B-B′ of FIG. 37 and a peripheral circuit cross sectionalview.

Referring to FIGS. 37 and 38, after formation of the third interlayerinsulation layer 3100, the third interlayer insulation layer 3100 may bepatterned to form a plurality of line-shaped contact grooves 3300 in thecell region using the same manners as described with reference to FIGS.6 and 7. Each of the line-shaped contact grooves 3300 may be designed tohave a width which is substantially equal to a sum of a width of eachcontact pattern 435 and substantially twice a width of each first spacer431 illustrated in FIG. 16.

FIG. 39 is a plan view illustrating an array layout of pseudo contactlines 4300 in the cell region, and FIG. 40 is a merged cross-sectionalview including a cell cross sectional view taken along lines A-A′ andB-B′ of FIG. 39 and a peripheral circuit cross sectional view.

Referring to FIGS. 39 and 40, pseudo contact lines 4300 may be formed inrespective line-shaped contact grooves 3300 (see FIG. 38) using the samemanners as described with reference to FIG. 9. While the contact lines430 of FIG. 9 are formed with a conductive layer, the pseudo contactlines 4300 may be formed with an insulation layer and may be removedwhen bit line contacts are formed in a subsequent process. The pseudocontact lines 4300 may be formed to include any insulation material(e.g., a silicon oxide layer) having an etch selectivity with respect tothe third interlayer insulation layer 3100 (e.g., a silicon nitridelayer).

FIG. 41 is a plan view illustrating an array layout of contactseparation mask patterns 4500 in the cell region, and FIG. 42 is amerged cross-sectional view including a cell cross sectional view takenalong lines A-A′ and B-B′ of FIG. 41 and a peripheral circuit crosssectional view.

Referring to FIGS. 41 and 42, contact separation mask patterns 4500(e.g., line-shaped etch mask patterns) may be formed substantially onthe substrate including the pseudo contact lines 4300. The contactseparation mask patterns 4500 may be formed to generally extend in adirection intersecting the pseudo contact lines 4300. For example, thecontact separation mask patterns 4500 may be formed to be generallyperpendicular to the pseudo contact lines 4300. That is, the contactseparation mask patterns 4500 may be formed using the same manners asdescribed with reference to FIGS. 10 and 11. The contact separation maskpatterns 4500 may be formed of an insulation material having an etchselectivity with respect to the pseudo contact lines 4300 (e.g., asilicon oxide layer) and the third interlayer insulation layer 3100(e.g., a silicon nitride layer). For example, the contact separationmask patterns 4500 may be formed to include an amorphous carbon layer.

As described with reference to FIGS. 10 and 11, the pseudo contact lines4300 (see FIG. 40) may be etched using the contact separation maskpatterns 4500 as an etch mask, thereby forming contact separationgrooves 4330. As a result of the etching process applied to the pseudocontact lines 4300, pseudo contact patterns 4350 may be formed generallyat intersections between the contact separation mask patterns 4500 andthe cell active lines 1110, respectively.

FIG. 43 is a merged cross-sectional view illustrating process steps offorming third spacers 4331 on sidewalls of the contact separationgrooves 4330.

Referring to FIG. 43, the contact separation mask patterns 4500 (seeFIG. 42) may be substantially removed. Subsequently, a spacer layer maybe deposited substantially on the substrate where the contact separationmask patterns 4500 are removed, and the spacer layer may beanisotropically etched to form third spacers 4331 substantially on thesidewalls of the contact separation grooves 4330. A width of the contactseparation grooves 4330 may be reduced because of the presence of thethird spacers 4331. The contact separation grooves 4330 may correspondto empty spaces where the pseudo contact lines 4300 exposed by thecontact separation mask patterns 4500 are selectively removed. Thus, awidth of the contact separation grooves 4330 may depend on a width ofthe pseudo contact lines 4300.

Each of the pseudo contact lines 4300 may be designed to have a widthwhich is substantially equal to the sum of a width of each contactpattern 435 and generally twice the width of each first spacer 431illustrated in FIG. 16, and each of the contact patterns 435 illustratedin FIG. 16 may be designed to have a width which is substantially equalto a width of each cell active line 1110 having a minor axis directionof the cell active lines 1110. Accordingly, a width of the contactseparation grooves 4330 may be greater than the width of the cell activelines 1110. The third spacers 4331 may reduce a substantial width of thecontact separation grooves 4330. That is, the third spacers 4331 mayreduce the width of active separation grooves that are formed to divideeach of the cell active lines 1110 into a plurality of cell activepatterns in a subsequent process. The third spacers 4331 may be formedto include an insulation material having an etch selectivity withrespect to both a silicon oxide layer and a silicon layer. For example,the third spacers 4331 may be formed to include a silicon nitride layer.

FIG. 44 is a merged cross-sectional view illustrating process steps offorming active separation grooves 1430.

Referring to FIG. 44, using the same manners as described with referenceto FIGS. 12 and 13, the cell active lines (1110 of FIG. 43) exposed bythe contact separation grooves 4330 may be etched to form activeseparation grooves 1430. The active separation grooves 1430 may begenerally defined by the third interlayer insulation layer 3100, thefirst isolation layer 2310 exposed by the contact separation grooves4330, the pseudo contact patterns 4350, and the third spacers 4331.

The pseudo contact patterns 4350 may include an insulation material, asdescribed above. Thus, the contact separation mask patterns 4500 (seeFIG. 42) may be removed prior to formation of the active separationgrooves 1430. Accordingly, the etching process for forming the activeseparation grooves 1430 may be performed using an etch recipe thatselectively etches the cell active lines 1110 and exhibits an etchselectivity with respect to the third interlayer insulation layer 3100,the first isolation layer 2310, the pseudo contact patterns 4350, andthe third spacers 4331. Each of the cell active lines 1110 may bedivided into a plurality of cell active patterns 1410 by the activeseparation grooves 1430.

FIG. 45 is a merged cross-sectional view illustrating process steps offorming a third isolation layer 2350 substantially filling the activeseparation grooves 1430.

Referring to FIG. 45, a third isolation layer 2350 may be formed tosubstantially fill the active separation grooves 1430 (see FIG. 44).Specifically, a separation groove liner 2150, for example, an insulationlayer may be conformed to substantially cover bottom surfaces andsidewalls of the active separation grooves 1430, as described withreference to FIGS. 14 and 15. Subsequently, the third isolation layer2350, for example, an insulation layer may be formed substantially onthe substrate including the separation groove liner 2150. The thirdisolation layer 2350 may be formed of substantially the same material asthe first isolation layer 2310. In an exemplary embodiment, the thirdisolation layer 2350 may be formed of a silicon nitride layer.

FIG. 46 is a merged cross-sectional view illustrating process steps ofexposing top surfaces of the pseudo contact patterns 4350.

Referring to FIG. 46, the third isolation layer 2350 may then beplanarized using a chemical mechanical polishing (CMP) process or anetch back process, thereby substantially exposing the top surfaces ofthe pseudo contact patterns 4350, the third interlayer insulation layer3100, and the third spacers 4331.

FIG. 47 is a merged cross-sectional view illustrating process steps offorming buried gates 5110.

Referring to FIG. 47, the third interlayer insulation layer 3100 and thecell active patterns 1410 may be etched using the same manners asdescribed with reference to FIGS. 18 and 19, thereby forming a pluralityof buried gate grooves 5010 substantially intersecting the cell activepatterns 1410. Subsequently, a buried gate layer may be formed tosubstantially fill the buried gate grooves 5010 using the same mannersas described with reference to FIGS. 20 and 21. The buried gate layermay be substantially recessed using the same manners as described withreference to FIGS. 22 and 23, thereby forming buried gates 5110 inrespective buried gate grooves 5010. As a result, sealing grooves 5130may be provided on the respective buried gates 5110.

FIG. 48 is a merged cross-sectional view illustrating process steps offorming sealing layers 5300 covering the buried gates 5110.

Referring to FIG. 48, a sealing layer 5300, for example, an insulationlayer may be deposited substantially on the substrate including thesealing grooves 5130 (see FIG. 47) using the same manners as describedwith reference to FIGS. 24 and 25. The sealing layer 5300 may be formedto substantially fill the sealing grooves 5130. The sealing layer 5300may be formed to include an insulation material (e.g., a silicon nitridelayer) having an etch selectivity with respect to the pseudo contactpatterns 4350 to protect the buried gates 5110 when a subsequent etchingprocess is performed. The sealing layer 5300 may be then planarized tosubstantially expose top surfaces of the pseudo contact patterns 4350.

FIG. 49 is a plan view illustrating an array layout of contact holes4351 in the cell region, and FIG. 50 is a merged cross-sectional viewincluding a cell cross sectional view taken along lines A-A′ and B-B′ ofFIG. 49 and a peripheral circuit cross sectional view.

Referring to FIGS. 49 and 50, the exposed pseudo contact patterns 4350may be selectively removed to form contact holes 4351. The contact holes4351 may substantially expose central portions of the cell activepatterns 1410 and may function as bit lines contact holes.

FIG. 51 is a plan view illustrating an array layout of contact patterns4352 in the cell region, and FIG. 52 is a merged cross-sectional viewincluding a cell cross sectional view taken along lines A-A′ and B-B′ ofFIG. 51 and a peripheral circuit cross sectional view.

Referring to FIGS. 51 and 52, a conductive layer, for example, a dopedpolysilicon layer or a metal layer may be formed to substantially fillthe contact holes 4351, and the conductive layer may be planarized toform contact patterns 4352 in respective contact holes 4351.

FIG. 53 is a merged cross-sectional view illustrating process steps offorming a fourth interlayer insulation layer 3101.

Referring to FIG. 53, after formation of the contact patterns 4352, thethird interlayer insulation layer 3100 in the cell region may beselectively removed. In the event that the third interlayer insulationlayer 3100, the third spacers 4331 and the sealing layer 5300 may beformed of the same material (e.g., a silicon nitride layer), the thirdspacers 4331 and the sealing layer 5300 may be partially or entirelyremoved while the third interlayer insulation layer 3100 in the cellregion is selectively removed.

Subsequently, a fourth interlayer insulation layer 3101, for example, asilicon oxide layer may be formed on the substrate where the thirdinterlayer insulation layer 3100 in the cell region is selectivelyremoved. The fourth interlayer insulation layer 3101 may then beplanarized to substantially expose the top surfaces of the contactpatterns 4352.

FIG. 54 is a merged cross-sectional view illustrating process steps offorming a first peripheral gate layer 5510.

Referring to FIG. 54, the third interlayer insulation layer (3100 ofFIG. 53) remaining in the peripheral circuit region may be selectivelyremoved to substantially expose the peripheral active patterns 1130 inthe peripheral circuit region. A peripheral gate dielectric layer 5520,for example, a silicon oxide layer may be substantially formed on theexposed peripheral active patterns 1130, and a first peripheral gatelayer 5510 may be substantially formed on the substrate including theperipheral gate dielectric layer 5520.

FIG. 55 is a merged cross-sectional view illustrating process steps offorming a bit line layer 5700.

Referring to FIG. 55, the first peripheral gate layer 5510 in the cellregion may be selectively removed to substantially expose top surfacesof the contact patterns 4352 and the fourth interlayer insulation layer3101. A first barrier metal layer 5750, a bit line layer 5700 and a bitline capping layer 5900 may be sequentially formed on the substratewhere the first peripheral gate layer 5510 in the cell region isselectively removed.

FIG. 56 is a merged cross-sectional view illustrating process steps offorming bit line stacks 5770 and at least one peripheral gate stack5780.

Referring to FIG. 56, the bit line capping layer 5900 (see FIG. 55), thebit line layer 5700 (see FIG. 55), the first barrier metal layer 5750and the first peripheral gate layer 5510 (see FIG. 55) may be patternedto form bit line stacks 5770 in the cell region and at least oneperipheral gate stack 5780 in the peripheral circuit region.Accordingly, each of the bit line stacks 5770 may be formed to include afirst barrier metal pattern 5750, a bit line 5720, and a bit linecapping pattern 5910 which are sequentially stacked. Further, theperipheral gate stack 5780 may be formed to include a first peripheralgate 5540, a first barrier metal pattern 5750, a second peripheral gate5740, and a peripheral gate capping pattern 5930 which are sequentiallystacked.

As described with reference to FIGS. 28 and 29, the bit line stacks 5770and the peripheral gate stack 5780 may be independently formed using twoseparated patterning processes. Alternatively, the bit line stacks 5770and the peripheral gate stack 5780 may be simultaneously formed orformed generally at the same time using a single patterning process thatincludes a single exposure process and a single etching process, asdescribed with reference to FIGS. 28 and 29.

Using the same manners as described with reference to FIG. 30, bit linespacers 5870 may be formed substantially on the sidewalls of the bitline stacks 5770 and peripheral gate spacers 5880 may be formedsubstantially on the sidewalls of the peripheral gate stack 5780.

A sixth interlayer insulation layer 3500 may be formed to substantiallyfill spaces between the bit line stacks 5770 as well as generallybetween the peripheral gate stacks 5780, as described with reference toFIG. 31. Thus, an interlayer insulation layer stacked on both ends ofeach of the cell active patterns 1410 may include the fourth interlayerinsulation layer 3101 and the sixth interlayer insulation layer 3500,and both the fourth interlayer insulation layer 3101 and the sixthinterlayer insulation layer 3500 may be formed to include a siliconoxide layer. Each of the contact patterns 4352 may be substantiallysurrounded by the fourth interlayer insulation layer 3101, for example,a silicon oxide layer. In contrast, each of the contact patterns 435illustrated in FIG. 31 may be substantially surrounded by the sealinglayer 530, for example, a silicon nitride layer.

FIG. 57 is a merged cross-sectional view illustrating process steps offorming storage node contact holes 6010 in the cell region.

Referring to FIG. 57, using the same or similar manner as described withreference to FIGS. 32 and 33, the sixth interlayer insulation layer 3500and the fourth interlayer insulation layer 3101 may be patterned to fromstorage node contact holes 6010 that substantially expose both ends ofeach of the cell active patterns 1410. The storage node contact holes6010 may be formed to be generally self-aligned with the bit line stacks5770. After the storage node contact holes 6010 are formed using a dryetching process, the storage node contact holes 6010 may be generallyenlarged using a wet etching process. The wet etching process may beperformed using an oxide etchant such as a diluted hydrofluoric (HF)acid solution. Thus, the storage node contact holes 6010 may begenerally widened to increase widths thereof. That is, the widenedstorage node contact holes 6010 may laterally extend onto edges of thesealing layers 5300 to maximize the exposed areas of the cell activepatterns 1410. As a result, contact areas of the cell active patterns1410 may be maximized.

FIG. 58 is a merged cross-sectional view illustrating process steps offorming storage node contacts 6100 in the cell region.

Referring to FIG. 58, using the same or similar manners as describedwith reference to FIG. 34, storage node contacts 6100 may be formed inrespective widened storage node contact holes 6010 and storage nodes6300 may be formed on respective storage node contacts 6100.

The embodiments of the inventive concepts have been disclosed above forillustrative purposes. Those skilled in the art will appreciate thatvarious modifications, additions and substitutions are possible, withoutdeparting from the scope and spirit of the inventive concept asdisclosed in the accompanying claims.

What is claimed is:
 1. A method of fabricating a semiconductor device,the method comprising: forming a first isolation layer in asemiconductor substrate to define active lines; forming pseudo contactlines generally crossing over the active lines and a first interlayerinsulation layer substantially filling spaces between the pseudo contactlines; forming line-shaped etch mask patterns generally crossing overthe active lines and the pseudo contact lines; etching the pseudocontact lines exposed by the line-shaped etch mask patterns to formcontact separation grooves and to form pseudo contact patterns generallyremaining at intersections between the line-shaped etch mask patternsand the active lines; etching the active lines exposed by the contactseparation grooves to form active separation grooves that generallydivide each of the active lines into a plurality of active patterns;forming a third isolation layer substantially filling the activeseparation grooves; forming gates that substantially intersect theactive patterns; removing the pseudo contact patterns to form contactholes; forming contact patterns substantially filling the contact holes;and forming bit lines connected to the contact patterns.
 2. The methodof claim 1, wherein forming the pseudo contact lines includes: forming afirst interlayer insulation layer substantially on the substrateincluding the first isolation layer; etching the first interlayerinsulation layer to form line-shaped contact grooves; and filling theline-shaped contact grooves with a different insulation layer from thefirst interlayer insulation layer.
 3. The method of claim 1: wherein thefirst interlayer insulation layer is formed to include a silicon nitridelayer and the pseudo contact lines are formed to include a silicon oxidelayer; and wherein the line-shaped etch mask patterns are formed toinclude an amorphous carbon layer different from the first interlayerinsulation layer.
 4. The method of claim 1, further comprising formingspacers generally on sidewalls of the contact separation grooves afterformation of the contact separation grooves, wherein the activeseparation grooves are formed to be self-aligned with the spacers andthe first isolation layer exposed by the contact separation grooves. 5.The method of claim 4, wherein the spacers are formed to includesubstantially the same material as the first isolation layer.
 6. Themethod of claim 1, wherein forming the third isolation layer includes:forming a silicon nitride layer substantially filling the activeseparation grooves and the contact separation grooves; and planarizingthe silicon nitride layer to substantially expose top surfaces of thepseudo contact patterns.
 7. The method of claim 1, wherein forming thecontact patterns is followed by: recessing the first interlayerinsulation layer and the third isolation layer to substantially exposesidewalls of the contact patterns; and filling spaces between theexposed sidewalls of the contact patterns with a second interlayerinsulation layer including a different material from the third isolationlayer.
 8. The method of claim 7, wherein the second interlayerinsulation layer is formed to include a silicon oxide layer.
 9. Themethod of claim 1, wherein forming the gates includes: etching the firstinterlayer insulation layer and the active patterns to form generallyline-shaped buried gate grooves substantially intersecting the activepatterns; forming a buried gate layer substantially filling the buriedgate grooves; recessing the buried gate layer to form buried gates inrespective buried gate grooves and to provide sealing groovessubstantially on respective buried gates; and forming sealing layerssubstantially in respective sealing grooves.
 10. A method of fabricatinga semiconductor device, the method comprising: forming a first isolationlayer in a semiconductor substrate to define cell active lines in a cellregion of the semiconductor substrate and to define a peripheral activeregion in a peripheral circuit region of the semiconductor substrate;forming pseudo contact lines that generally cross over the cell activelines and a first interlayer insulation layer that substantially fillsspaces between the pseudo contact lines and substantially covers theperipheral circuit region; forming line-shaped etch mask patternsgenerally crossing over the cell active lines and generally crossingover the pseudo contact lines in the cell region; etching the pseudocontact lines exposed by the line-shaped etch mask patterns to formcontact separation grooves and to form pseudo contact patterns remainingat intersections substantially between the line-shaped etch maskpatterns and the cell active lines; etching the cell active linesexposed by the contact separation grooves to form active separationgrooves that generally divide each of the cell active lines into aplurality of cell active patterns; forming a third isolation layerfilling the active separation grooves; forming buried gates thatsubstantially intersect the cell active patterns; selectively removingthe pseudo contact patterns to form contact holes; forming contactpatterns substantially filling the contact holes; selectively removingthe first interlayer insulation layer in the peripheral circuit regionto substantially expose the peripheral active region; forming a firstperipheral gate layer on the peripheral circuit region including theexposed peripheral active region; forming a bit line layer electricallyconnected to the contact patterns on an entire surface of the substrateincluding the first peripheral gate layer; and patterning the bit linelayer and the first peripheral gate layer to form bit lines connected tothe contact patterns in the cell region and to form a peripheral gateincluding a first peripheral gate and a second peripheral gate in theperipheral circuit region, wherein the first peripheral gate is aportion of the first peripheral gate layer and the second peripheralgate is a portion of the bit line layer.